The treatments which are applied to semi-conductor materials during the manufacture of devices such as diodes, transistors, integrated circuits, solar cells, etc . . . imply one or more annealing phases. These annealings are designed to produce, depending on the cases, one of the following phenomena: crystallization of a layer of an amorphous semi-conductor material deposited on a substrate; re-crystallization in solid or molten phase, then surface re-crystallization of a crystalline material with a view to obtaining a crystal growing; structural reconstitution of a superficial layer destroyed by the ionic implantation of doping impurities; and re-distribution of the doping impurities near the surface of a semi-conductor material.